Ecoregions

New Caledonia rainforests

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By Eric Gaba (Sting - fr:Sting) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Introduction

The islands of New Caledonia contain some of the most distinctive plants in the world, with a large number of species, endemics, and an ancient character to much of the flora. The New Caledonia rainforests are the richest part of the French territory, but they have suffered large losses of native habitat.

Location and General Description

caption Riviere Bleue Reserve, New Caledonia. (Photograph by David Olson)

New Caledonia is located in the southwest Pacific Ocean about 1200 kilometres (km) east of Australia and 1500 km northeast of New Zealand. The main island of Grande Terre runs in a north-south orientation and is 16,372 square kilometers (km2). Unlike the much smaller neighboring islands, which are volcanic and relatively recent in origin, Grand Terre is an original piece of Gondwanaland. It separated from Australia 85 million years ago and has maintained its current isolation from other landmasses for more than 55 million years. Isolation and an ancient source of plant life are major factors leading to its diverse flora, but they are not the only factors. Grand Terre has an extremely diverse soil substrate, with ultramafics forming about one-third of the island. It is also diverse topographically and climatically. Grand Terre is the only high island of New Caledonia, with a mountain chain running down the center of the island and five peaks exceeding 1500 metres (m). Many smaller ranges and valleys run counter to the island's north-south orientation. The soils of the Loyalty Islands to the east and Iles des Pines to the south of Grand Terre are largely from limestone substrates that resulted from the volcanic uplifting of corals when the islands were formed.

caption WWF

Rainfall in New Caledonia is highly seasonal. Trade winds bring the rains, which usually come from the east. The average annual rainfall is about 1500 millimetres (mm) for the Loyalty Islands, 2000 mm for the low elevation eastern Grand Terre, and 2000 to 4000 mm at high elevations. The western side of Grand Terre receives much less rainfall because of the orographic nature of the island's weather (see description for New Caledonia dry forests).

The tropical moist forest of this ecoregion is generally subdivided into lowland rainforests of the Loyalty Islands and Grand Terre, the montane forests of Grand Terre, and Grand Terre's wet maquis forest. The lowland tropical rainforests are of a mixed-species composition, with the prevalent gymnosperms being Agathis lanceolata, A. ovata, Araucaria columnaris, A. bernieri, Dacrydium araucarioides, Dacrycarpus vieillardii, and Falcatifolium taxoides. The main angiosperm trees include Montrouziera cauliflora, Calophyllum neocaledonicum, Dysoxylum spp., Neogullauminia cleopatra, Hernandia cordigera, and species of the genera Kermadecia, Macadamia, and Sleumerodendron. In some places single-species dominant stands of Araucaria, Callistemon, and Nothofagus occur. Montane rain forest species include Araucaria, Agathis, Podocarpus, Dacrydium, Libocedrus, Acmopyle, Metrosideros, Weinmannia, Quintinia, and Nothofagus. The unique maquis forests on Grande Terre are dominated by Araucaria species and are unique. Their scrublike structure resembles that of Mediterranean climate woodlands. However, the maquis of New Caledonia are a response to the ultramafic substrate rather than the climate.

Biodiversity Features

caption Kagu (Rhynochetos jubatus), New Caledonia. (Photograph by Arnaud Greth)

New Caledonia has five endemic plant families (Amborellaceae, Oncothecaceae, Papracrypyiaceae, Phellinaceae, and Strasburgiaceae) out of a total of 196 families found on the islands. Nearly 14 percent of the plant genera and 79.5 percent of the species are endemic. The percentage of endemic species is greater than that of all other Pacific island groups, with the exception of Hawaii (89 percent) and New Zealand (81.9 percent), and is comparable to continental levels of endemism. However, Hawaii contains only 956 species, compared with New Caledonia's 2,973. New Zealand shares New Caledonia's Gondwanaland history, but even New Zealand has fewer total species and fewer total endemics, although the North Island alone is seven times larger than New Caledonia. The lower numbers for New Zealand probably result from a less diverse substrate and its location outside the tropics.

Plant numbers obscure an underlying theme to New Caledonia's unique biodiversity. Part of what makes New Caledonia so unique is the large number of ancient lineages and absence of widespread genera and families. The ancient nature of plants in particular is exemplified by Amborella trichopoda, the only species in the family Amborellaceae, thought to be one of the closest living relatives to the first angiosperms (flowering plants) and the high number of woody species that lack vessels, a feature typical of primitive families. New Caledonia has a remarkable diversity of gymnosperms (primitive nonflowering plants that include conifers), with forty-four species (forty-three of which are endemic) out of fifteen genera (at least three of which are endemic). Eric Dinerstein, chief scientist for WWF, commented in a recent National Geographic article that when in New Caledonia, "I feel like I'm walking in a forest the dinosaurs knew."

Table 1. Endemic and Near-Endemic Mammal Species.
Family Species
Pteropodidae Notopteris macdonaldi
Pteropodidae Pteropus ornatus
Pteropodidae Pteropus vetulus
Vespertilionidae Chalinolobus neocaledonicus
Vespertilionidae Miniopterus robustior*
Vespertilionidae Nyctophilus sp.
An asterisk signifies that the species' range is limited to this ecoregion.

 

Like New Caledonia's plant life, terrestrial animals are represented often by unique species and ancient lineages, but many types of widespread species are missing. There are no native amphibians, three snakes (none of which is on Grand Terre), and only nine mammals species, all of which are bats (six of which are either endemic or near endemic; Table 1). All of New Caledonia's sixty-eight lizards (sixty of which are endemic) are from just three families: geckos (Gekkonidae and Diplodactylidae) and skinks (Scincidae). Both families of reptiles contain recent arrivals as well as ancient Gondwanaland groups. The birds of New Caledonia consist mainly of modern forms. However, one ancient family, Rynochetidae, is endemic to New Caledonia and is currently represented by one species, the kagu (Rhynochetos jubatus). The kagu is the national bird of New Caledonia and is listed by IUCN as endangered (EN), along with the Australasian bittern (Botaurus poiciloptilus), New Caledonian lorikeet (Charmosyna diadema), and New Caledonian owlet-nightjar (Aegotheles savesi). The most precarious existence, however, may belong to the New Caledonian rail (Gallirallus lafresnayanus), which IUCN listed as critical (CR). IUCN listed five other bird species as vulnerable (VU) to extinction. A total of seven birds are endemic to the ecoregion, but there are twenty-four near endemics (Table 2). Additionally, two bats are considered endangered (Chalinolobus neocaledonicus and Miniopterus robustior), and two more are vulnerable (long-tailed fruit bat, Notopteris macdonaldi, and ornate flying-fox, Pteropus ornatus).

Table 2. Endemic and Near-Endemic Bird Species.
Family Common Name Species
Accipitridae White-bellied goshawk Accipiter haplochrous
Rallidae New Caledonian rail Gallirallus lafresnayanus*
Rhynochetidae Kagu Rhynochetos jubatus*
Columbidae Red-bellied fruit-dove Ptilinopus greyii
Columbidae Cloven-feathered dove Drepanoptila holosericea*
Columbidae New Caledonian imperial-pigeon Ducula goliath
Loriidae New Caledonian lorikeet Charmosyna diadema*
Psittacidae Horned parakeet Eunymphicus cornutus
Aegothelidae New Caledonian owlet-nightjar Aegotheles savesi
Campephagidae Melanesian cuckoo-shrike Coracina caledonica
Campephagidae New Caledonian cuckoo-shrike Coracina analis
Campephagidae Long-tailed triller Lalage leucopyga
Sylviidae New Caledonian grassbird Megalurulus mariei
Acanthizidae Fan-tailed gerygone Gerygone flavolateralis
Eopsaltriidae Yellow-bellied robin Eopsaltria flaviventris
Monarchidae Southern shrikebill Clytorhynchus pachycephaloides
Monarchidae New Caledonian flycatcher Myiagra caledonica
Rhipiduridae Streaked fantail Rhipidura spilodera
Pachycephalida New Caledonian whistler Pachycephala caledonica
Zosteropidae Large Lifou white-eye Zosterops inornatus*
Zosteropidae Green-backed white-eye Zosterops xanthochrous
Zosteropidae Small Lifou white-eye Zosterops minutus*
Meliphagidae New Caledonian myzomela Myzomela caledonica
Meliphagidae Cardinal myzomela Myzomela cardinalis
Meliphagidae Dark-brown honeyeater Lichmera incana
Meliphagidae New Caledonian friarbird Philemon diemenensis
Meliphagidae Crow honeyeater Gymnomyza aubryana*
Meliphagidae Barred honeyeater Phylidonyris undulata
Estrildidae Red-throated parrotfinch Erythrura psittacea
Sturnidae Striated starling Aplonis striata
Corvidae New Caledonian crow Corvus moneduloides
An asterisk signifies that the species' range is limited to this ecoregion.

 

Some of the vertebrate species of New Caledonia stand out for being unique in size: the New Caledonian imperial-pigeon (Ducula goliath) is the largest arboreal pigeon in the world, Rhacodactylus leachianus is the world's largest gecko, and the giant skink (Phoboscincus bocourti) is the largest skink, although it has not been seen since the 1870s and may be extinct.

Current Status

The New Caledonia rainforests have suffered large losses of native habitat. Rainforests in New Caledonia used to occupy 70 percent of the land area and now occupy 21.5 percent. Logging and mining are decreasing as logging operations are becoming localized, and the degree of mining has been scaled back from the boom years of the 1960s and 1970s. Still, New Caledonia produces about half of the world's nickel and contains 40 percent of the world's known nickel deposits. The past impacts of these land uses are severe. Deforestation and large-scale open mines have given New Caledonia some of the worst soil erosion in the world. The accessibility of forests to hunting is increased by both logging and prospecting and threatens some species such as the New Caledonian imperial-pigeon.

Maquis makes up the remainder of the ecoregion and naturally covers much of the ultramafic substrates that contain high concentrations of nickel, iron, magnesium, olivine, and chromium. Mining therefore has been the main land use destroying maquis, but this has been localized. The soil of maquis will not support agriculture, and the vegetation is too scrublike for timber. Maquis vegetation is expanding primarily into disturbed areas at mid to low elevation.

The protected area network of New Caledonia is poor both in size (covering 2.8 percent of the land area) and in resources, making the protected areas little more than paper parks (Table 3). The Rivière Bleue Park is an exception, being well managed and having some of the only resident park personnel. The park also has the only kagu populations that are on the rise as a result of controlling introduced predators. One glaring gap in New Caledonia's biodiversity protection is the lack of protected areas in the Loyalty Islands.

Table 3. WCMC Protected Areas That Overlap with the Ecoregion.
Protected Area Area (km2) IUCN Category
Twenty nature reserves (no names in database) 370 ?
Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.

Types and Severity of Threats

The main threats to rainforests in New Caledonia have been and will continue to be widespread logging, mining, and wildlife hunting. However, introduced species are a growing problem in New Caledonia. Pigs, goats, cats, dogs, and rats present problems for native species here, as they do on many islands throughout the world. New Caledonia also has Java deer (Cervus timorensis) that are widely hunted. In addition to deer trampling and grazing understory plants, people often start fires to attract deer to the new growth that follows. In addition to setting fire for deer, Bouchet et al. explained, "lighting fire has also become an expression of protest from young rural unemployed males. It is not exaggerated to write that fires plague New Caledonia, west and east coast alike, from July to December." Many of the native species are not adapted to be fire resistant, and as a result some introduced species and native species that are fire resistant are taking over. The Neotropical ant (Wassmannia auropunctata) that was brought in with Caribbean pine cultivation is diminishing native lizard and invertebrate abundance and diversity. The severe impacts of this ant may determine the long-term persistence of native communities in this ecoregion.

New Caledonia is a prosperous territory of France, and this prosperity affects the future of its biodiversity. The per capita income of New Caledonia is similar to that of New Zealand and Australia. The prosperity means that many of the problems of rapid population increases found in other tropical forested areas are not prevalent. However, because New Caledonia, as part of France, is considered a developed country, it does not qualify for funds to protect biodiversity through traditional international sources. Meanwhile, the French government has paid little attention to the conservation of New Caledonia's wealth of biodiversity.

Justification of Ecoregion Delineation

The New Caledonia rain forests ecoregion is based on the original extent of humid forests appearing in Jaffré and Veillon. All other islands of New Caledonia (including the Loyalty Islands and Iles des Pines) have been included as part of the ecoregion based on assumptions of rainfall vegetation descriptions appearing in Mueller-Dombois. Habitats within the ecoregion include subregions of maquis forests, montane and lowland forests, and savannas.

Additional Information on this Ecoregion

  • For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
  • To see the species that live in this ecoregion, including images and threat levels, see the WWF Wildfinder description of this ecoregion.

 

Disclaimer: This article contains information that was originally published by the World Wildlife Fund. Topic editors and authors for the Encyclopedia of Earth have edited its content and added new information. The use of information from the World Wildlife Fund should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.

 

 

Glossary

Citation

Fund, W. (2014). New Caledonia rainforests. Retrieved from http://www.eoearth.org/view/article/154831

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